package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    /**
     * 开始时间戳 2000-1-1
     */
    private static final long BEGIN_TIMESTAMP = 1640995200L;
    /**
     * 序列号的位数
     */
    private static final int COUNT_BITS = 32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;


    public long nextId(String keyPrefix) {
        // 1.生成时间戳
        long newTime = LocalDateTime.now().toEpochSecond(ZoneOffset.UTC);
        long timeStamp = newTime - BEGIN_TIMESTAMP;

        // 2.生成序列号，使用redis的自增id
        // 2.1.获取当前日期，精确到天，可以很方便的统计到每年每天每月的订单量
        String date = LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        // 2.2.自增长
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);

        // 3.拼接并返回
        return timeStamp << 32 | count;

    }
}